I've been using WP PM with my team since I installed it last week. I love the idea of having a PM system that works within WP. I decided to use one of my unused domains to install it. There are Pros and Cons:

PROS:
1. Love that I can create separate project
2. It's great that I can have discussions within a project
3. The ability to have private projects and tasks is cool too
4. The support desk is very responsive and helpful

CONS (only one but it's major):
1. Lack of notifications onsite causes extra work to go back and forth with email to see when comments are made in projects. I would prefer that a notification popup appear or somehow a notification alert onsite happens. Right now, I'm missing communications from my team members. Especially if I'm busy on a project and not watching my email. Not having this feature is holding me back from stacking and from completely moving over to WP PM.